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+/* Run-time dynamic linker data structures for loaded ELF shared objects.
+Copyright (C) 1995 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#ifndef	_LINK_H
+#define	_LINK_H	1
+
+#include <elf.h>
+
+
+/* Rendezvous structure used by the run-time dynamic linker to communicate
+   details of shared object loading to the debugger.  If the executable's
+   dynamic section has a DT_DEBUG element, the run-time linker sets that
+   element's value to the address where this structure can be found.  */
+
+struct r_debug
+  {
+    int r_version;		/* Version number for this protocol.  */
+
+    struct link_map *r_map;	/* Head of the chain of loaded objects.  */
+
+    /* This is the address of a function internal to the run-time linker,
+       that will always be called when the linker begins to map in a
+       library or unmap it, and again when the mapping change is complete.
+       The debugger can set a breakpoint at this address if it wants to
+       notice shared object mapping changes.  */
+    Elf32_Addr r_brk;
+    enum
+      {
+	/* This state value describes the mapping change taking place when
+	   the `r_brk' address is called.  */
+	RT_CONSISTENT,		/* Mapping change is complete.  */
+	RT_ADD,			/* Beginning to add a new object.  */
+	RT_DELETE,		/* Beginning to remove an object mapping.  */
+      } r_state;
+
+    Elf32_Addr r_ldbase;	/* Base address the linker is loaded at.  */
+  };
+
+/* This symbol refers to the "dynamic structure" in the `.dynamic' section
+   of whatever module refers to `_DYNAMIC'.  So, to find its own
+   `struct r_debug', a program could do:
+     for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL)
+       if (dyn->d_tag == DT_DEBUG) r_debug = (struct r_debug) dyn->d_un.d_ptr;
+   */
+
+extern Elf32_Dyn _DYNAMIC[];
+
+
+/* Structure describing a loaded shared object.  The `l_next' and `l_prev'
+   members form a chain of all the shared objects loaded at startup.
+
+   These data structures exist in space used by the run-time dynamic linker;
+   modifying them may have disastrous results.  */
+
+struct link_map
+  {
+    /* These first few members are part of the protocol with the debugger.
+       This is the same format used in SVR4.  */
+
+    Elf32_Addr l_addr;		/* Base address shared object is loaded at.  */
+    char *l_name;		/* Absolute file name object was found in.  */
+    Elf32_Dyn *l_ld;		/* Dynamic section of the shared object.  */
+    struct link_map *l_next, *l_prev; /* Chain of loaded objects.  */
+
+    /* All following members are internal to the dynamic linker.
+       They may change without notice.  */
+
+    const char *l_libname;	/* Name requested (before search).  */
+    Elf32_Dyn *l_info[DT_NUM];	/* Indexed pointers to dynamic section.  */
+    const Elf32_Phdr *l_phdr;	/* Pointer to program header table in core.  */
+    Elf32_Word l_phnum;		/* Number of program header entries.  */
+
+    /* Symbol hash table.  */
+    Elf32_Word l_nbuckets;
+    const Elf32_Word *l_buckets, *l_chain;
+
+    unsigned int l_opencount;	/* Reference count for dlopen/dlclose.  */
+    enum			/* Where this object came from.  */
+      {
+	lt_executable,		/* The main executable program.  */
+	lt_interpreter,		/* The interpreter: the dynamic linker.  */
+	lt_library,		/* Library needed by main executable.  */
+	lt_loaded,		/* Extra run-time loaded shared object.  */
+      } l_type:2;
+    unsigned int l_deps_loaded:1; /* Nonzero if DT_NEEDED items loaded.  */
+    unsigned int l_relocated:1;	/* Nonzero if object's relocations done.  */
+    unsigned int l_init_called:1; /* Nonzero if DT_INIT function called.  */
+    unsigned int l_init_running:1; /* Nonzero while DT_INIT function runs.  */
+  };
+
+/* Internal functions of the run-time dynamic linker.
+   These can be accessed if you link again the dynamic linker
+   as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
+   but are not normally of interest to user programs.
+
+   The `-ldl' library functions in <dlfcn.h> provide a simple
+   user interface to run-time dynamic linking.  */
+
+
+/* File descriptor referring to the zero-fill device.  */
+extern int _dl_zerofd;
+
+/* OS-dependent function to open the zero-fill device.  */
+extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
+
+/* OS-dependent function to give a fatal error message and exit
+   when the dynamic linker fails before the program is fully linked.
+   All arguments are `const char *'; args until a null pointer
+   are concatenated to form the message to print.  */
+extern void _dl_sysdep_fatal (const char *string, ...)
+     __attribute__ ((__noreturn__));
+
+/* Nonzero if the program should be "secure" (i.e. it's setuid or somesuch).
+   This tells the dynamic linker to ignore environment variables.  */
+extern int _dl_secure;
+
+/* This function is called by all the internal dynamic linker functions
+   when they encounter an error.  ERRCODE is either an `errno' code
+   or zero; ERRSTRING is a string describing the specific problem.  */
+   
+extern void _dl_signal_error (int errcode, const char *errstring)
+     __attribute__ ((__noreturn__));
+
+/* Call OPERATE, catching errors from `dl_signal_error'.  If there is no
+   error, *ERRSTRING is set to null.  If there is an error, *ERRSTRING is
+   set to the string passed to _dl_signal_error, and the error code passed
+   is the return value.  */
+extern int _dl_catch_error (const char **errstring, void (*operate) (void));
+
+
+/* Helper function for <dlfcn.h> functions.  Runs the OPERATE function via
+   _dl_catch_error.  Returns zero for success, nonzero for failure; and
+   arranges for `dlerror' to return the error details.  */
+extern int _dlerror_run (void (*operate) (void));
+
+
+/* Open the shared object NAME and map in its segments.
+   LOADER's DT_RPATH is used in searching for NAME.
+   If ENTRY_POINT is not null, fill it in with the object's entry point.
+   If the object is already opened, returns its existing map.  */
+extern struct link_map *_dl_map_object (struct link_map *loader,
+					const char *name,
+					Elf32_Addr *entry_point);
+
+/* Cache the locations of MAP's hash table.  */
+extern void _dl_setup_hash (struct link_map *map);
+
+
+/* Search loaded objects' symbol tables for a definition of the symbol
+   referred to by UNDEF.  *SYM is the symbol table entry containing the
+   reference; it is replaced with the defining symbol, and the base load
+   address of the defining object is returned.  SYMBOL_SCOPE is the head of
+   the chain used for searching.  */
+extern Elf32_Addr _dl_lookup_symbol (const char *undef,
+				     const Elf32_Sym **sym,
+				     struct link_map *symbol_scope);
+
+
+/* List of objects currently loaded.  */
+extern struct link_map *_dl_loaded;
+
+/* Tail of that list which were loaded at startup.  */
+extern struct link_map *_dl_startup_loaded;
+
+/* Allocate a `struct link_map' for a new object being loaded,
+   and enter it into the _dl_loaded list.  */
+extern struct link_map *_dl_new_object (char *realname, const char *libname,
+					int type);
+
+/* Relocate the given object (if it hasn't already been).
+   If LAZY is nonzero, don't relocate its PLT.  */
+extern void _dl_relocate_object (struct link_map *map, int lazy);
+
+/* Return the address of the next initializer function not yet run.
+   When there are no more initializers to be run, this returns zero.
+   The functions are returned in the order they should be called.  */
+extern Elf32_Addr _dl_init_next (void);
+
+/* Call the finalizer functions of all shared objects whose
+   initializer functions have completed.  */
+extern void _dl_fini (void);
+
+/* The dynamic linker calls this function before and having changing
+   any shared object mappings.  The `r_state' member of `struct r_debug'
+   says what change is taking place.  This function's address is
+   the value of the `r_brk' member.  */
+extern void _dl_r_debug_state (void);
+
+
+#endif /* link.h */